CSYSERS 






By Walter Harvey Weed. 



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GEYSERS 




DEPARTMENT OF THE INTERIOR 

1912 

WASHINGTON :GOVERNMENT PRINTING OFFICE : 191 



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This publication may be purchased from the Superintendent of Docu 
ments, Government Printing Office, Washington, D. C. for lo cents. 



VAY20 191? 



GEYSERS. 



By Walter Harvky Weed. 



GENERAL STATEMENT. 

The hot-water fountains, called geysers, are natural wonders that are 
of general as well as scientific interest. The striking manifestation 
which they afford of the earth's internal heat, their great beauty, and 
novel surroundings make them indeed worthy of that widespread inter- 
est which they arouse, and it is in the hope of gratifying a general curi- 
osity concerning these wonderful fountains that the present paper has 
been written. 

At the outset of this inquiry into the nature and occurrence of these 
natural steam engines it is necessary to exactly define what is a geyser. 
Briefly, a geyser is a hot spring which intermittently ejects a column of 
boiling water and steam. Before attempting to present such a general 
account of the various geyser regions of the world as will enable the 
reader to follow the deductions derived from a study of the occurrence 
and the characteristics of geysers, it may be well to present a summary 
of the paper. 

It is believed that the facts recorded in this article show : 

First. That geysers occur only in volcanic regions and in acid volcanic 
rocks. In Iceland and New Zealand the volcanic fires are still active. 

vSecond. Geysers occur only along lines of drainage, on shores of lakes 
or other situations where meteoric waters would naturally seek the surface. 

Third. Geyser waters are meteoric waters which have not penetrated 
to great depths, but have been heated by ascending vapors. 

Fourth. The supply of heat is derived from great masses of lava slowly 
cooling from a state of former incandescence, heating waters, which, 
descending to the hot rocks, ascend as highly heated vapors. 

3 



4 GEYSERS. 

Fifth. The intermittent spouting of geysers is due to the gradual heating 
of water accumulated in fissures or tubes in the rocks, the only mecha- 
nism necessary being a tube, which may or may not have local expansions 
or chambers. 

Sixth. Geysers may originate in several ways, though most commonly 
produced by the opening of new waterways along fissure planes of the 
rocks, by a gradual eating out of a tube by ascending hot vapors. 

Seventh. The thermal activity of geyser regions is not rapidly dying 
out. The decrease of heat is very slow, and, though changes take place 
from year to year, the establishment of new geysers and new hot springs 
offsets the decay or drying up of old vents. 

Attempts to solve the mysterious spouting of geysers date back to 
the earlier part of the present epoch of scientific research and the genius 
of Bunsen and Deseloiseaux was devoted to a study of the Iceland geysers 
as early as 1847. The most important result of their experiments and 
observations was a theory of geyser action, now (with slight modifica- 
tions) generally accepted, but other conclusions have been proven by 
observations made in the Yellowstone Park to be erroneous. Although 
numerous visits to the geysers of Iceland by later obser\'ers led to various 
ingenious speculations and theories respecting geyser eruptions, the cjues- 
tions of geyser origin and the significance of their occurrence and other 
questions of broader scope were not touched upon. 

In looking at the distribution of geysers in various parts of the world, 
one is quickly impressed with their great rarity. Hot springs abound in 
many countries, but boiling springs are characteristic only of regions of 
recent (that is, geologically recent) volcanic activity; only in such 
regions do geysers occur. Until late in the last century Iceland was the 
only land where geysers had been found. Less than 60 years ago they 
were discovered in considerable numbers in New Zealand, and since then 
a few others have been reported from other parts of the world. The 
"Geyserland" of the world is undoubtedly, however, the Yellowstone 
National Park, a region situated in the heart of the Rocky Mountains, at 
the headwaters of the Missouri and Yellowstone. 

In order to bring before the reader a general idea of the true relation 
of geyser vents to the surrounding topography and watercourses of the 
districts, a brief description of the great geyser regions of the world 
will be attempted. It has been my good fortune to have spent seven 
summers at the various geyser "basins" of the Yellowstone in connection 
with my duties as assistant geologist on the United States Geological 
Survey party under Arnold Hague. The other regions are familiar from 
a large series of excellent photographs, as well as through the descriptions 
of friends and the writings of other visitors to those countries. 




New Crater Geyser, Norris Basin. 

Photograph by F. J. Haynes. 




Constant Geyser, Norris Basix. 

Photograph by F. J. Haynes. 



6 GEYSERS. 

THE ICELAND GEYSERS. 

Iceland is the birthplace of the word geyser. It has been called the 
land of frost and fire, and indeed in no place are the evidences — nav, the 
very forces themselves — of frost and fire brought so forcibly in contrast. 
The island is eminently a volcanic region, a central table-land with 
sharp volcanic peaks, hooded with great Jokuls, or glaciers, mantled with 
perpetual snows, and surrounded by a more or less narrow strip of low- 
land bordering upon the sea. The evidences of internal fire are unmis- 
takable. Hecla and other volcanoes are occasionally active, and the 
whole island is covered with lava poured out by the volcanoes, and the 
source of the heat supplying the geysers is unquestioned. 

As would naturally be expected from the combination of water and 
fire, hot springs are abundant and at a few localities geysers are found. 
The most noteworthy of these is Haukadal, where The Geyser, Strokr, 
and a smaller geyser are found. This locality is about 70 miles from 
Reykiavik, the Iceland metropolis, and is only reached on horseback 
over beds of clinkers and rough lava fields; a dreary ride so far as scenery 
goes, but of fresh novelty to visitors from warmer lands. The hot springs 
are clustered in an area of about 20 acres, at the base of a hill about an 
eighth of a mile long and 300 feet high, and at the edge of the marshy 
bottom that stretches out toward the Hvita River. The springs are 
really at the base of the seaward border of the high ground, where the 
waters that have percolated through the tufas and porous lavas of the 
higher region would come to the surface. The two geysers Strokr and 
The Geyser issue from mounds of gray or white silica deposited by the 
hot waters, and the neighboring springs are surrounded by lesser areas 
of the same material, while on the hillside back of the springs the rock is 
decomposed by the steam of fumeroles. These two large spouters show- 
two types of geysers. Strokr has a funnel-like pit 36 feet deep and 8 feet 
across (see page 27), expanding into a saucer-like basin. The tube 
is generally filled to within 6 feet of the top with clear water, which boils 
furiously, owing to the escape of great bubbles of steam coming from two 
openings in opposite sides of the tube. The eruptions are quite as beau- 
tiful as those of its more famous companion, the jets rising in a sheaf-like 
column to a height of 100 or more feet, eruptions taking place at very 
irregular and long intervals; but by putting a lid on this great kettle, by 
dumping in large pieces of turf, an eruption can be produced in a short 
time. 

The Geyser, on the contrary, is a pool of limpid green water whose 
surface rises and falls in rhythmic pulsations. The usual temperature 
is but 170° F. or 200° F., but varies, being greater immediately before 
an eruption. The shallow saucer-like basin is about 60 feet across and 
slopes gently to a cylindrical shaft to feet in diameter, forming the pipe 




Fountain Geyser, Lower Basin. 

Photograph by F. J. Haynes. 





Great Fountain Geyser, Lowicr Basin. 
Photograph by F. J. Haynes. 



8 GEYSERS. 

of the geyser; this is about 70 feet deep. This regularity of the tube be- 
comes important when we consider Bunsen's experiments and the theory 
of geyser action he deduced from them. Before an eruption bubbles 
of steam entering the tube suddenly collapse with loud but muffled re- 
ports and a disturbance of the quiet surface of the water. During this 
simmering, for such it is, the water rises in dome-like mounds over the 
pipe and overflows the basin, running down the terraced slope and wet- 
ting the cauliflower-like forms of sinter that adorn it. 

The eruptions that so long puzzled and astonished visitors to this 
remote land are surpassed by those of the giants of the Yellowstone, but 
their beauty is not less. A short time before Geyser plays, the domes of 
water rising in the center of the basin come in quick succession and 
finally burst into spray, followed by a rapid succession of jets increasing 
in height until the column is 100 feet high. Dense clouds of steam 
momentarily hide the glistening sheaf of jets, hiding it from sight, then 
drifting away in the breeze again reveal the sparkling shaft. 

These eruptions have varied much in appearance and height since the 
geyser was first known. At present the column does not exceed 90 feet 
and the eruption lasts but a few moments. After it the basin is empty 
and seems to be lined with a smooth coating of white silica. 

THE GEYSERS OF NEW ZEALAND. 

The geysers of New Zealand are situated in a region clothed with a 
luxuriant vegetation that is in strong contrast to the bleak and barren 
lava fields of Iceland, but an examination of the position of the springs, 
with respect to the physical features of the region, shows that the situa- 
tion of the geysers is nearly the same in these antipodal isles. The New 
Zealand geysers occur in the North Island, in what is known as the 
volcanic region, or the Taupo zone. Within an area of 4,725 square miles, 
in which none but volcanic rocks are found, there are six volcanoes and 
great numbers of solfataras, fumeroles, mud volcanoes and hot springs, 
and many geysers. The lavas are all of the acid type, mostly rhyolite, 
but are hidden by surface decomposition and an abundant vegetation, 
save upon the flanks of the peaks. The axial line of this zone running 
northeast is marked at each end by an active volcano and its course by 
a line of greatest hydrothermal activity, a sinuous line of hot springs 
following well-marked geographic features of river valleys, low plains, 
and lake margins, with higher country on either side rising to plateaus of 
2,000 to 3,000 feet above the sea. 

Little is known of the geysers on the shores of Lake Taupo or those 
on the banks of the Waikato River, but the famous terraces of Rotoma- 
hana, called the eighth wonder of the world by James Anthony Froude, 
attracted attention to the geysers which formed them, and made their 




Grotto Geyser, Upper Basin. 

Photograph by F. J. Haynes. 




Riverside Geyser, Upper Basin. 

Photograph by F. J. Haynes. 



30919°— 12 2 



lO GEYSERS. 

vicinity the best-known part of the district. The warm lake called 
Rotomahana by the Maoris was a shallow body of warm water about a 
mile long and a quarter of a mile broad, comprising 185 acres. The 
waters were of a dirty greenish hue, reflecting the somber green of the 
fern and the ti-tree-covered slopes about it, and the sedgy margins shel- 
tered large numbers of duck and other water fowl. Rising above its sur- 
face like stairways of delicately sculptured marble Avere the pink and 
white terraces. At the top of the terrace, 120 feet above the lake, was 
the Terata Geyser, whose overflow had built up this wonderful work and 
filled the basins and pools with waters whose tints were both the delight 
of the eye and the despair of the pen. 

The geyser caldron was some 60 by 80 feet across, its clear and boiling 
water usually overflowing and occasionally ejected to a height of 40 to 
100 feet, wetting the steep banks of bright-colored fumerole clays about 
the crater but not forming the beaded geyserite characteristic of so 
many of these fountains. Such eruptions followed a period of quiescence, 
when the waters retired within the pipe for many hours. Owing to the 
comparative inaccessibility of the caldron and the beauty of the terraces, 
but few observations are on record of the action of the geyser. The 
water carried 150 grains of solid matter to the gallon, of which one-third 
was silica, and the daily outflow of 100,000 to 600,000 gallons per hour 
brought up 10 tons of solid matter dissolved out of the underlying rocks. 
It is easy to see what great underground caverns would be formed by this 
geyser alone in a comparatively brief time. In the volcanic outbreak of 
Tarawera, in June, 1886, the waters of the lake and underground reser- 
voirs were drawn into the newly opened fissure, and, by the extraordinary 
explosion that followed, the terraces were destroyed and the site of 
Rotomahara became a crater that threw mud over the surrounding 
country. 

THE YELLOWSTONE " GEYSERLAND." 

The wonderful variety, the great number, and the large size of the 
geysers of America, found in the Yellowstone National Park, demand a 
somewhat longer account of this region. The geysers are found in de- 
tached groups, occup3'ing basins or valleys of the great table-land which 
forms the central portion of the park, a region whose heavy forests and 
uninviting aspect, combined with the rugged nature of the encircling 
mountain ranges, so long proved a barrier to exploration, even to those 
adventurous trappers and prospectors of the Great West. 

The geyser "basins," as the localities are termed, conform, in their re- 
lations to the surrounding high ground and their coincidence with lines 
of drainage and the loci of springs, to the laws governing the distribu- 
tion of the same phenomena in other parts of the world. The park itself 
is a reservation of about 3,500 square miles, the central portion being an 




o 



2 « 
o § 




o 



12 



GEYSERS. 



elevated volcanic plateau, accentuated by deep and narrow canyons and 
broad srentle eminences and surrounded bv high and rugged mountain 




vSkktch Map of Norris Geyser Basix. 



ranges. This central portion, whose average elevation is about 8,000 
feet above the sea, embraces all the hot-spring and geyser areas of the 
park. The volcanic activity that resulted in the formation of the park 




Spoxge Spring, Upper Basin. 

Photograph by F. J. Haynes. 




I'COX 



iMIC (■>i:vSI;k, I'l'l'ICK F.ASIN. 
Photograph by V. J. Haynes. 



14 



GEYSERS. 



plateau may be considered as extinct, nor are there any evidences of 
fresh lava flows. Yet the hot springs so widely distributed over the 
plateau are convincing evidence of the presence of underground heat. 
There is no doubt that the waters derive their high temperature from 
the heated rocks below, and that the origin of the heat is, in some way, 
associated with the source of volcanic energv. 




The various geyser basins, or fire holes, as they were called by the first 
explorers, each possess individual peculiarities which give character 
and interest to each locality. The most noted of these "basins" is, how- 
ever, that known as the Upper Geyser Basin of the Firehole River, one 
of the headwaters of the great Missouri. This "Upper Basin," as it is 
generally called, lies a little westward of the center of the park. It is a 
valley \}4 miles long by one-half mile broad, inclosed by the rocky clifl's 



GEYSERS. 



15 



or darklv wooded slopes of the great Madison Plateau and drained by 
the Firehole River, along whose banks the largest geysers are situated. 
The whole floor of the valley is fairly riddled with springs of boiling water, 
whose exquisite beauty is indescribable. Light clouds of fleecy vapor 
curl gently upward from waters of the purest azure or the clearest of 




emerald, and, encircling rims of white marblelike silica, form fit setting 
for such great gems. A large part of the valley floor is covered with the 
white deposit of silica known as siliceous sinter, deposited by the over- 
flowing hot waters.* The weird whiteness of these areas, the gaunt white 
trunks of pine trees killed by the hot waters, the myriad pools of steam- 
ing crystal, and the white clouds floating off" from the chimney-like geyser 



• See " Formation of Hot Spring deposits. 
Survey, 1889. 



W. H. Weed Ninth Ann. Rept. Director of U. S. Geological 




2; Z. 

o o 



i8 



GEYSERS. 



cones, form a scene never to be forgotten by those fortunate enough to 
behold it. Within this basin there are nearly 30 geysers, presenting 
many variations of bowl or basin, mound and cone, and whose eruptions 
are equally diversified in form and beauty. 

Sentinel, Fan, Cascade, Riverside, Mortar, and Grotto greet one on 
entering the basin either by quiet steaming or by flashing jets. Giant, 
Splendid, Castle, Grand, Giantess, Lion, and Old Faithful are but a few 
of the wondrous fountains of the place. The last is most deserving of 
its name. Ever since its discovery, in 1870, it has not failed to send 
up a graceful shower of jets at intervals of 60 to 75 minutes. Its 




Excelsior Geyser. 

Photograph by F. J. Hayaes. 

beauty is ever varying, as wind and sunlight play upon it, and the 
mound about its vent is adorned with delicately tinted basins of salmon, 
pink, and yellow, filled with limpid water whose softness is enticing. It 
is the geyser of the park, and indeed of the world, and many a visitor 
to "geyserland" departs without seeing any other of the many spouters 
in action and yet feels more than repaid for the journey. For beauty of 
surroundings the Castle will perhaps be awarded the palm; its sinter 
chimney or cone is formed of exquisite cauliflower or coral-like geyserite, 
whose general form makes the geyser's name appropriate. Its eruptions 
are frequent, occurring about every 24 hours, when a stream of hot 
water is thrown up to a height of 75 feet for about 30 minutes, followed 
by the emission of steam, with a loud roar that can be heard for miles. 



GEYSERS. 



^9 



A few hours after the eruption the tube is again full, and occasional jets 
of ID to 20 feet are thrown out until the next eruption ensues. 

The greatest geyser of the park, and indeed the grandest of the whole 
world, was Excelsior, some 25 miles beyond the Norris Basin. Unlike the 
less capricious and more fountain-like geysers of the Upper Firehole, this 
monster of geysers did not spout from a fissure in the rock, nor from a 
crater or cone of itsown building. It was a monster of destruction, having 
torn out its great crater in the old sinter-covered slope, builded by the 
placid and beauteous Prismatic Lake. The walls, formed by the jagged 
ends of the white sinter layers, were lashed by the angry waters that were 
ever undermining the sides and enlarging the caldron. The eruptions 
were so stupendous that all other geysers are dwarfed by comparison. 
The grand outburst was preceded by several abortive attempts, when great 
domes of water rose in the center and burst into splashing masses 10 to 
15 feet high, while the waters surged under the overhanging walls and 
overflowed the slope between the crater and the river. Finally, with a 
grand boom or report that shook the ground, an immense fan-shaped 
mass of water was thrown up to a height of 200 or more feet, great clouds 
of steam rolled off from the boihng water, while large blocks of the white 
sinter were flung far above the water and fell about the neighboring slopes. 
Unfortunately, this monarch of all geysers has ceased to erupt. 

Everywhere, save at the Norris Basin of the Yellowstone Park, geyser 
vents are surrounded by cones, mounds, or platforms of white siliceous 
sinter, which, though built up into very beautiful forms, hides the true 
relation of the geyser vent to the fissures in the rocks, so that it has been 
generally believed, as stated by Tyndall,^ that the hot springs built up 
tubes of siUceous rock, that made them geysers. That this is not true 
is shown by several great fountains at the Norris Basin, that spout 
directlv from fissures in the solid rock, notably the Monarch, Tippecanoe, 
and Alcove geysers. 

Prominent geysers and springs, based upon ohservalicns during season igii. 
NORRIS BASIN. 



Name. 


Height. 


Duration of eruption. 


Intervals of eruption. 




Feet. 








10 




yi minute. 


Congress Pool (large boiling 
spring). 






30 




45 to ?o minutes. 


Emerald Pool (beautiful hot 
spring). 






6- 8 

IOO-I2S 

10- 20 

60 




Continuous. 






I to 1 minutes. 






Irregular, 6 or 7 days. 




I minute 


5 to 11; minutes. 






24 hours. 









Heat as a Mode of Motion 



20 GEYSERS. 

Prominent geysers and springs, based upon observations during season igii — Continued. 

LOWER BASIN. 



Name. 


Height. 


Duration of eruption. 


Intervals of eruption. 


Black Warrier, Steady, and 


Feet. 




White Dome (small but inter- 
esting geysers). 
Clepsydra 


10- 40 
200-300 




3 minutes. 

Ceased playing in 1888. 






Firehole Lake (peculiar phe- 




nomena). 


20- 75 
75-150 




4 to 6 hours. 
Do 


Great Fountain 




Mammoth Paint Pots (basin of 






boiling clay). 
Prismatic Lake (size about 2 so by 






400 feet; remarkable coloring). 
Turquoise Spring (about 100 feet 








in diameter). 









UPPER BASIN. 



Artemisia 

Atomizer 

Bee Hive 

Castle 

Comet 

Cubs (chimneys to Lion and 
Lioness). 

Daisy 

Economic 



Fan 

Giant 

Giantess 

Grand 

Grotto 

Jewel 

Lion 

Lioness 

Mortar 

Oblong 

Old Faithful. 
Riverside. . . . 

Sawmill 

Spasmodic. . . 
Splendid .... 
Turban 



NOTABLE SPRINGS. 

Black Sand Spring (about 55 by 
60 feet). 

Chinaman 

Emerald Pool , 

Morning Glory 

Punch Bowl 

Sponge 

Sunset Lake 



50 

2 

200 

50- 75 

60 

10- 30 

70 
20 

15- 25 

200-250 

150-200 

200 

20- 30 
30- 40 
50- 60 
80-100 
30 
20- 40 
125-150 
80-100 

20- 35 

4 

200 

20- 40 



10 minutes ! 24 hours (varies). 



8 to 20 minutes. 

30 minutes 

Short 



2 minutes. . . . 
Few seconds. 



10 minutes 

60 minutes 

12 hours 

40 to 60 minutes 

About one-half hour . 

About I minute 

About 8 minutes. . . . 
About 10 minutes. . . 

4 to 6 minutes 

Several minutes 

4 minutes 

15 minutes 

1 to 2 hours 

2 minutes 

10 minutes 

20 minutes 



7 to 9 days. 
24 to 2b hours. 
Irregular. 



About 60 minutes. 
5 minutes for about 2 days 
following the Grand. 

4 to 8 hours. 

7 to 12 days, 
irregular. 

Do. 
2 to 5 hours. 

5 minutes. 
Irregular. 

Do. 
2 hours. 

8 hours. 

60 to 75 minutes. 
About 7 hours. 
2 to 3 hours. 

Do. 
Not played since 1892. 
Irregular. 



GEYSER WATERS. 



The descriptions which have been given of the chief geyser regions 
of the world lead to the question, What is the source and character of 
the geyser waters? It has been plainly indicated that in the fields de- 
scribed the vents are always situated along lines of drainage, on the 
shores of lakes, or under conditions where ordinary springs of meteoric 
water would naturally occur. 

That the geyser waters are surface waters which have percolated 
through the porous lavas and have been heated by encountering great 




Black Growler, Norris Basin. 

Photograph by F. J. Haj-nes. 




Mud Geyser. 

Photograph by F. J. Haynes. 



22 GEYSERS. 

quantities of steam and gases rising from the hot rocks below there is no 
reasonable doubt. The proximity of ordinary cold springs and those of 
boiling hot water lends support to this view. 

These hot waters, traversing the rocks in irregular fissures, readily 
dissolve out the more soluble constituents of the rocks, the amount and 
the character of the salts present varying somewhat with the nature and 
amount of gases held in the waters. Chemical analyses of geyser waters 
from the three regions described show no greater variation than those 
from different vents in any one of these regions. 

Source of heat. — That the source of steam is the still hot lavas below, 
and is in some way connected with volcanic action, is so evident from 
the facts that no other conclusion is possible. A very common belief 
concerning the source of the heat of boiling springs and geysers, but 
one which no longer has the support of scientific men, is that the heat 
results from chemical action, as it is vaguely termed. Were not the 
evidence so directly opposed to this idea, it would merit consideration, 
but so far as the heat of geyser waters is concerned all observation shows 
it to be untenable. To this class of theories belongs the popular idea 
that the geyser basins are underlain by great beds of (quick?) lime, 
which supply the heat and steam of the geysers. 

The smothered combustion of beds of lignite, coal, or pyrites is an- 
other form of the same theory that has been received with considerable 
favor and still commands a few followers. That hot springs may have 
such an origin is not denied, but the geological conditions and environ- 
ment clearly show that none of the great geyser regions of the world 
derive their heat from such action. 

Where the source of supply is deep-seated, spring waters always have 
an elevated temperature, generally proportionate to the depth, but the 
very high temperatures of the geysers and the local source of the waters 
exclude this theory. The folding and faulting of rocks is another source 
of heat made manifest by hot springs. 

It has been shown b\ Dr. Peale, however, that boiUng waters are only 
found in the regions of volcanic rocks, and it was pointed out by L'Ap- 
parent that geysers only occur in acid volcanic lavas. In Iceland the 
volcanic forces are still active, and melted lavas may exist at no great 
depth. In New Zealand the recent eruption of the eroded mountain 
Tarawera showed that heated rocks exist and in that case rose up near 
enough to the surface to cause the explosion which so transformed the 
country. 

In the Yellowstone there are no active volcanoes, and none of even 
geologically recent activity. The lavas that fill the ancient mountain- 
encircled basin of the park are scored by glaciers and deeply cut by 
running water, and the old volcanoes from which the lavas were, in part 
at least, outpoured show no signs of having been active since Tertiary 
times. Yet in this region the expenditure of heat by the hot springs, 




W C8 



H j2 
'■'3 ,- 

O M 







24 GEYSERS. 

gevsers, and steam vents would undoubtedly keep a moderate-sized 
volcano in a very active state were it concentrated. There is no doubt 
that this heat is connected with the past volcanic energies of the region 
and derived principally from the still hot lavas, three-quarters of the 
entire area of the park (3,500 square miles) being covered by rhyolitic 
rocks. 

The significance alluded to above, of the association of geysers and 
acid lavas (rhyolites) , is possibly to be found in the fact that these rocks 
are more easily dissolved by the hot waters forming the tubes and reser- 
voirs for geysers. The situation of hot springs and geysers along water- 
courses has already been mentioned. It is a well-known fact that the 
presence of water in the pores of a rock increases its capacity to conduct 
heat, so that we may surmise a rise in the local isogeotherm in such 
situations. 

Geyser eruptions. — Geysers have often been compared to volcanoes, 
presenting in miniature, with water instead of molten rock, all the phe- 
nomena of a volcanic eruption. The diversity of form and varying con- 
ditions of activity of the hot springs found associated with geysers makes 
it impossible to determine in every case whether a spring is or is not a 
geyser. Geyser vents may be mere rifts in the naked rocks or bowls of 
clear and tranquil water, quiet until disturbed by the first throes of an 
eruption, and surrounded by white sinter deposits in nowise distin- 
guishable from those about hot springs. In other cases the vents are 
surrounded by a cone or mound of pearly beaded "geyserite," a certain 
and distinctive feature of a geyser. 

The displays of the great "Geyser" of Iceland have already been 
briefly described ; they may be taken as the type of eruptions from gey- 
sers having bowl-like expansions at the top of the tube, the so-called 
"basin" of the geyser. Where the vent is surrounded by a cone of 
sinter, as is so often the case among the fountains of New Zealand and 
the Yellowstone, the first part of the geyser eruption is somewhat differ- 
ent. Perhaps the most familiar geyser of this type is Old Faithful, the 
one geyser in the Yellowstone that is sure not to disappoint the visitor. 
Though surpassed by many of its neighbors in the height and magnitude 
of its eruptions, it holds a front rank for beauty and gracefulness. Pre- 
viously heralded by loud rumblings, with spasmodic outbursts of 10 to 
20 feet in height that mark abortive attempts to send up its steaming 
pillar, the white column is finally thrown upward with a loud roar, and 
mounts at once to a height that seems hundreds of feet as we gaze upon 
it. For two or even three minutes the column maintains a height 
which measurements show to vary from 90 feet up to 150 feet, with occa- 
sional steeple-shaped jets rising still higher, the jets ever varying and 
giving off great rolling clouds of steam ; then the jets gradually decrease 
in altitude, and in five minutes the eruption is over, the tube apparently 
empty, and emitting occasional puffs of steam for a few minutes longer. 







J '^ 




S W 



2: a 
w 2 



26 GEYSERS. 

During the eruption the water falls in heavy masses about the vent, 
filling the basins that adorn the mound, and flowing off in yellow and 
orange-colored waterways, while the finer spray drifts off with the breeze 
and falls upon the neighboring sinter slopes. It is impossible to measure 
the amount of water thrown out, since it runs off in a number of directions 
in shallow rills that lead either to the sandy terrace near by or to the 
river. If, however, we assume that the column of steam and water is 
one-third water, a fair assumption, the estimated discharge is 3,000 bar- 
rels at each eruption. 

Comparing Old Faithful with its Iceland prototype we find considerable 
difference in the behavior of the two vents during the interval between 
eruptions. The former, like Strokr, has no bowl or basin, and the geyser 
throat or tube is partly filled with water, which is in constant and ener- 
getic ebullition while the geyser is inactive. The tube and bowl of 
"Geyser" are, on the contrary, filled with comparatively cool water. In 
each case, however, the eruption is preceded by an overflow from the 
geyser tube, in the case of Strokr and Old Faithful, as jets of 10 feet to 
25 feet in height; in "Geyser" by a filling of the bowl and successive 
overflows, accompanied by the noise of condensing steam bubbles, a sim- 
mering of the water in the tube. Such preliminary actions are significant 
when we consider the theory of geyser action. 

It is unnecessary to describe the numerous other theories of geyser 
action; they all suppose caverns or systems of chambers and tubes, of 
definite arrangement, a supposition most unlikely to occur in many cases, 
and made unnecessary by Bunsen's theory. Local expansions and irregu- 
larities of the tube do exist, and to them we owe many of the individual 
peculiarities of geysers, but such chambers do not form a vital, essential 
part of the geyser mechanism. 

In an excellent resume of the various theories of geyser action, Dr. 
A. C. Peale states that he believes no one theory is adequate to explain 
all the phenomena of geyser action, though Bunsen's theory comes nearest 
to it.i 

Where the tube is surrounded at the top by a basin no actual overflow 
need occur. Indeed there is in the Yellowstone a miniature geyser, 
aptly named the Model, with a tube but 2 inches in diameter, surrounded 
by a shallow, saucerlike basin, which has eruptions about every 15 
minutes of 3 feet to 5 feet in height in which scarcely a drop of water 
is wasted, but flows back into the tube after the eruption. During the 
interval between eruptions no water can be seen in the tube, whose basin 
and upper part are dry and cool. The first signal of the coming display 
is a quiet welling up of the water in the tube filling the little basin, which 
being relatively large and shallow relieves the water column of a consid- 
erable height. During the eruption which follows, the spray is chilled 
by the air, falling back into the basin; at the end of the display the water 
is quickly sucked back into the tube and reheated for the ensuing eruption. 

1 Twelfth Ann. Rept. U. S. Geol. and Geog. Survey Territories, vol. n., p. 422. 



GEYSERS. 



27 



At first thought the constant boiling of the waters in the tube of 
Strokr, Old Faithful, and many other geysers seems to oppose the theory 
which we have just given. Observations show however that in many 
cases the boiling is confined to the surface and deep temperatures do not 
reach the boiling point corresponding to the depth. It is quite likely 
also that in some cases a lesser and independent supply of heat may 
connect with the upper part of a geyser tube; Strokr, we know, has two 
vents (see figure), one of which is the geyser tube, the funnellike throat 
of Strokr being really but a nozzle to the geyser. 

Theories of geyser action. — The intermittent spouting of geysers was 
long a riddle to scientific men, for although several theories seemed each 



Obser 





Strokr 



-10 
■?.o 

■30 
-hO 

zo 

-CjO 

-70 
--75/eet. 

Geyser 

SECTION'S OF Geyser and Strokr Showing Fissures Stltpplying Geyser Tubes 

(After Campbell). 

to offer a satisfactory explanation of the eruptions of "Geyser," they 
supposed conditions unlikely to occur in many vents. The investiga- 
tions of Bunsen, and of Descloizeaux, who spent two weeks studying the 
Iceland fountains, resulted in the announcement of a theory of geyser 
action which, with slight modifications, has satisfied all requirements 
and is to-day generally accepted as the true explanation of the action of 
these natural steam engines. This theory, which bears the name of the 
illustrious Bunsen, depends upon the well-known fact that the boiling 
point of water rises with the pressure, and is therefore higher at the 
bottom of a tube of water than at the surface. The temperature of water 
heated in any vessel is generally equalized by convective currents, but 
in a long and narrow or an irregular tube this circulation is impeded, and 
while the water at the surface boils at 100° C. (at sea level), ebullition in 
the lower part of the tube is only possible at a much higher temperature, 



28 GEYSERS. 

owing to the weight of the water column above it. In the section of 
Geyser shown in the figure the observed temperatures are given on the 
left, and the temperatures at which the waters would boil, taking into 
account the pressure of the water column, are given on the right. In 
Geyser the nearest approach to the boiling point is at a depth of 45 
feet opposite a ledge and fissure discovered subsequent to Bunsen's ex- 
periments. At this depth the temperature is 2° C. below the tempera- 
ture at which the water can boil. If by the continued heating of this 
layer by steam from the fissure it attains the temperature at which it can 
boil, steam is formed, whose expansive force lifts the superincumbent 
column of water, causing a slight overflow at the top, which, shortening 
the column, brings the layer B to the position C, where its temperature is 
above the boiling point of C, wherefore steam is formed at this point and 
a further lifting and relief of pressure ensues, followed by an eruption. 

In illustration of this theory a model geyser is easily constructed of 
a glass tube an inch or so in diameter and several feet long. When 
this tube is closed at one end, filled with water and placed upright we 
have all the mechanism necessary to produce all the phenomena of a 
geyser. By heating the water at the bottom by the introduction of 
steam (or with a spirit lamp), we can produce eruptions whose period 
will depend upon the intensity of the heat. At first the bubbles of steam 
collapse in the cool waters at the bottom of the tube, but as the tem- 
perature rises the bubbles rise part way up the tube and heat the lower 
part of the column to a high temperature while the water near the sur- 
face is still cool. Eventually the water at the bottom reaches the pres- 
sure boiling point, when steam is formed, lifting the water above it and 
causing an overflow at the top. This overflow or its equivalent, the 
filling of a shallow basin at the top of the tube relieves the pressure and 
all that part of the column whose temperature was previously below the 
boiling point but now exceeds it, flies into steam and ejects the water 
above with great violence. The glass walls of our geyser tube permit us 
to watch the gradual heating of the water by means of thermometers 
suspended in the tube, the ascent and collapse of steam bubbles, the 
overflow and abortive attempts to erupt and the final ejection of the 
water from the tube. 

I believe, however, that Bunsen's theory is a perfect explanation if 
we but admit that the geyser tube may be neither straight nor regular, 
but of any shape or size, and probably difi'ering very much for each 
vent. The shape of the bowl or basin exercises but little influence upon 
the eruption save to produce the many individual peculiarities of the 
geyser column. 

Origin of geysers. — It should be noted that Bunsen's theory of geyser 
action is quite independent of his theory of geyser formation. The 
building up of a siliceous tube by the evaporation of the waters at the 
margin of a hot spring is a process which may be seen in operation in 
any of the geyser regions of the world; but it is not a necessary pre- 



GEYSERS. 29 

lude to the formation of a geyser, for a simple fissure in the rock 
answers equally well, as is shown at the Norris geyser basin in the 
Yellowstone Park. 

The life history of a geyser varies, of course, for each one, but obser- 
vations show that the following sequence of events often takes place. 
The hot vapors rising from unknown depths penetrate the rocks along 
planes of fracture and shrinkage cracks, decomposing and softening 
the rock until the pressure of the steam and water is sufficient to force 
an opening to the surface. If this opening affords an easier exit for 
waters issuing at a higher level, the fissure is probably opened with a 
violent ejection of mud and debris; more often the process is a gradual 
one, accompanying the slow eating away of the rock walls along the 
fissure. The flowing waters slowly clear out the fissure, forming a tube 
that permits the freer escape of hot water and steam, while at the same 
time the waters change from a thick mud to a more or less clear fluid. 
The spring, at first a simple boiling mudhole, is now an intermittently 
boiling spring, which soon develops true geyser action. If the open- 
ing of the fissure afforded a new outlet for the waters of some already 
existing geyser, these changes take place rapidly, and eruptions begin 
as soon as the pipe is sufficiently cleared to hold enough water. The 
bare rock about the vent or fissure is soon whitened by silica deposited 
by the hot waters. This sinter may form a mound about the expanded 
tube or basin, or, if the vent shall be small and spray is frequently ejected, 
it builds up the curious geyser cones so prominent in the Yellowstone. 
In certain cases the building up of these deposits may partially choke 
the geyser's throat and cause a diminution of the geyser's energy, 
whose forces seek an easier outlet. In other cases the eating out of 
new subterranean waterways deprives the geyser of its supply of heat, 
and the vent becomes either tranquil or wholly extinct, while the 
pearly geyserite forming its cone disintegrates and crumbles into 
fine shaly debris, resembling comminuted oyster shells. Thus there is 
a slow but continual change in progress at the geyser basins, in which 
old springs become extinct and new ones come into being and activity. 

With few exceptions, where the vents are very new, geysers spout 
from basins or from cones of white siliceous sinter, or geyserite, depos- 
ited about the vent by the hot waters. Such deposits are formed very 
slowly, one-twentieth of an inch a year being an average rate of growth 
for the deposit formed by evaporation alone. These deposits of sinter 
are therefore an index to the age of the geyser. In many cases these 
sinter cones are very odd, fantastic structures of great beauty while wet 
by the geyser spray, but becoming white, opaque, and chalk-like upon 
drying. Where the spattered drops fall in a fine spray the deposit is 
pearly and the surface very finely spicular. If the spray be coarse, the 
rods are stouter and capped by pearly heads of lustrous brilliancy. 
Thus the cone is not only a measure of a geyser's age and activity, but 
it tells, in a way, the nature of the eruption. 



PUBLICATIONS ON YELLOWSTONE NATIONAL PARK. 

DEPARTMENT OF THE INTERIOR. 

The following publications may be obtained on application to the Sec- 
retary of the Interior: 
General information regarding the Yellowstone National Park, 32 pages. 

This pamphlet contains information regarding the hotels, camps, and transportation lines oper- 
ated in the park. It contains also sketch maps, tables of distances between principal points cf 
interest, lists of books and magazine articles on the park, and general information of interest to 
the tourist. 
Magazine articles on national parks, reservations, and monuments, 16 pages. 

A list of magazine articles on the Yellowstone and other parks. 
National park pictures collected and exhih-ted by the Department of the Interior, 
16 pages. 

A descriptive list of pictures exhibited by the Department of the Interior. Contains short descrip- 
tions by well-known writers of scenes in the larger national parks. 

SUPERINTENDENT OF DOCUMENTS. 

The following pubUcations may be obtained from the Superintendent 
of Documents, Government Printing Office, Washington, D. C: 
Geological history of the Yellowstone National Park, by Arnold Hague, 24 pp., 

illustrated. Price, 10 cents. 

The Superintendent of Documents has for sale also the earlier reports 
of explorations in the Yellowstone Park. A price list will be forwarded 
on application. 

GEOLOGICAL SURVEY. 

The following publications may be obtained from the Director of the| 
Geological Survey, Washington, D. C: 
Monograph 32, pt. 2, Descriptive geology-, petrography, and paleontology of the| 

Yellowstone National Park, 893 pp., illustrated. Price, $2.45. 
Atlas of the geology of the Yellowstone National Park, 27 sheets folio. Price, $3.75. 
Geologic Folio, No. 30, containing topographic and geologic maps of the park and a I 

description of the geology, 6 pages folio, 3 sheets folio illustrations, 8 sheets folidj 

maps. Price, 50 cents. 
Bulletin 395, Radioactivity of the thermal waters of the Yellowstone National Park,! 

35 pages. Free. 
Topographic map of the Yellowstone National Park, on a scale of 2 miles to the inch. 

Price, 20 cents. 



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017 056 714 6 



